1. Field of the Invention
The present invention has for an object agents for the simultaneous dyeing and brightening of keratin fibers, for example wool, silk or hair and particularly human hair, and which contain at least one thiazolium dye.
2. Description of Related Art
Two coloring methods are usually used for the color-changing treatment of keratin fibers. By the first method, the coloring is accomplished with oxidative or permanent colorants and by the use of a mixture of different developers and couplers and an oxidant. By this method, if necessary, a direct (non-oxidative) dye can be added if the coloring result is to be adjusted or special coloring effects are to be achieved. The second method involves the exclusive use of direct dyes which in an appropriate carrier composition are applied to the fibers. This method is easy to apply, very gentle and causes only minor damage to the keratin fibers. The direct dyes used for this purpose are subject to many requirements. For example, they must be unobjectionable in toxicological and dermatological terms and must make it possible to attain colorations of a desired intensity which, among other things, presupposes sufficient water solubility. Moreover, the colorations obtained must exhibit good light stability, acid resistance and abrasion resistance.
Compared to oxidative colorations, non-oxidative ones as a rule exhibit lower durability and a less adequate color balance. In addition, direct dyes usually cannot “impart to the hair a brighter shade”, because many direct dyes do not tolerate the oxidants needed for brightening and/or the required pH which is higher than or equal to 9.